1. Field of the Invention
The present invention relates to paper punches, i.e. punches for perforating sheets of paper for insertion into loose-leaf ring binders, and, more particularly, to user friendly, i.e. ergonomic, paper punches.
2. The Prior Art
Punches for perforating sheets of paper for insertion into loose-leaf ring binders and for retention therein have been known for many years. Typically, a paper punch includes a metal base and a metal upper plate pivotally attached thereto. Mounted between the base and the upper plate are several punch heads, wherein, when the upper plate is pressed toward the base, it rotates about the pivot attachment, forcing the punch heads to extend into mating holes in the base. When pressure is released from the upper plate, a spring forces the upper plate back to its inoperative position, retracting the punch heads from their mating holes.
Typically, the base is hollow for holding the paper punch-outs. The bottom wall of the base is a tray and is removable to allow for disposal of the punch-outs. The tray may be a pliable plastic so it can be removed from the metal base. As such, it is not an integral part of the base and may tend to become lost.
There are two general method of using a paper punch: on a flat surface, such as table desk top, or held in one's hand. When used on a flat the base is set on the flat surface, the paper is between the punch heads and mating holes, and the operator presses down the upper plate. If the operator's hand is too far back on the upper plate, the paper punch may rock backwards when the plate is pressed. As a result, the front of the base may lift from the table top, thereby causing paper to slip out and the punched holes to be misaligned. Also, because the typical upper plate is rigid and smooth the operator's hand may tend to slip when applying pressure, thereby also causing the paper slippage and punched hole misalignment.
When being used as a hand-held device, the paper punch is cradled in the operator's hand so that, when the hand is clenched, the base and upper plate are squeezed together. With a rigid and smooth upper plate or base, it may be difficult, especially for an operator with a small hand, to grip the paper punch securely and comfortably. In particular, because the edges of the plate and base typically are sharp, the edges jab into the operator's hand. In addition, an operator with a small hand may not have the leverage necessary for punching in the maximum number of sheets that the paper punch can accommodate.